From 1ab5258243a012cb372ea4c0772b13a288a127df Mon Sep 17 00:00:00 2001
From: Bastian Venthur <venthur@debian.org>
Date: Mon, 27 Sep 2021 21:16:11 +0200
Subject: Check for truthiness so empty strings are also false

---
 feedgenerator/django/utils/feedgenerator.py |  4 ++--
 tests_feedgenerator/test_feedgenerator.py   | 35 ++++++++++++++++++++++++++++-
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/feedgenerator/django/utils/feedgenerator.py b/feedgenerator/django/utils/feedgenerator.py
index 6631788..03994b6 100644
--- a/feedgenerator/django/utils/feedgenerator.py
+++ b/feedgenerator/django/utils/feedgenerator.py
@@ -325,9 +325,9 @@ class Atom1Feed(SyndicationFeed):
             handler.endElement("author")
         # try to use description or subtitle if provided, subtitle has
         # precedence above description
-        if self.feed['subtitle'] is not None:
+        if self.feed['subtitle']:
             handler.addQuickElement("subtitle", self.feed['subtitle'])
-        elif self.feed['description'] is not None:
+        elif self.feed['description']:
             handler.addQuickElement("subtitle", self.feed['description'])
         for cat in self.feed['categories']:
             handler.addQuickElement("category", "", {"term": cat})
diff --git a/tests_feedgenerator/test_feedgenerator.py b/tests_feedgenerator/test_feedgenerator.py
index 7370954..e44eadb 100644
--- a/tests_feedgenerator/test_feedgenerator.py
+++ b/tests_feedgenerator/test_feedgenerator.py
@@ -110,7 +110,18 @@ class TestFeedGenerator(unittest.TestCase):
         )
         feed = feedgenerator.Atom1Feed(**FIXT_FEED)
         result = feed.writeString(ENCODING)
-        assert "<desciption></description>" not in result
+        assert "<subtitle></subtitle>" not in result
+
+        # case 1.b: neither should be in
+        FIXT_FEED = dict(
+            title="title",
+            link="https://example.com",
+            description="",
+            subtitle="",
+        )
+        feed = feedgenerator.Atom1Feed(**FIXT_FEED)
+        result = feed.writeString(ENCODING)
+        assert "<subtitle></subtitle>" not in result
 
         # case 2: only description should be in
         FIXT_FEED = dict(
@@ -123,6 +134,17 @@ class TestFeedGenerator(unittest.TestCase):
         result = feed.writeString(ENCODING)
         assert "<subtitle>description</subtitle>" in result
 
+        # case 2.b: only description should be in
+        FIXT_FEED = dict(
+            title="title",
+            link="https://example.com",
+            description="description",
+            subtitle="",
+        )
+        feed = feedgenerator.Atom1Feed(**FIXT_FEED)
+        result = feed.writeString(ENCODING)
+        assert "<subtitle>description</subtitle>" in result
+
         # case 3: only subtitle should be in
         FIXT_FEED = dict(
             title="title",
@@ -134,6 +156,17 @@ class TestFeedGenerator(unittest.TestCase):
         result = feed.writeString(ENCODING)
         assert "<subtitle>subtitle</subtitle>" in result
 
+        # case 3.b: only subtitle should be in
+        FIXT_FEED = dict(
+            title="title",
+            link="https://example.com",
+            description="",
+            subtitle="subtitle",
+        )
+        feed = feedgenerator.Atom1Feed(**FIXT_FEED)
+        result = feed.writeString(ENCODING)
+        assert "<subtitle>subtitle</subtitle>" in result
+
         # case 4: both are in, only subtitle should be in
         FIXT_FEED = dict(
             title="title",
-- 
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